On Windows Server 2012 R2, WSUS won’t install because it’s waiting for user input, but doesn’t display anything on the screen. To install WSUS on Windows Server 2012 R2, you have to kick of the install from the management page (add features, etc), then you’ll see a yellow exclamation mark on the manage my server page. Click on the yellow exclamation mark and click Launch Post-Deployment Configuration. The WSUS service will then complete the install.